COMPARISON OF DIFFUSER-EJECTOR PERFORMANCE WITH FIVE DIFFERENT DRIVING FLUIDS
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFS TN
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An investigation was conducted to determine the diffuser-ejector performance for five different driving fluids--air, nitrogen, argon, helium, and hydrogen--having different ratios of specific heats. Two diffuser-ejector configurations, which consisted of two different area ratio nozzles and two duct sizes which gave duct-to-nozzle area ratios of 73.06 and 20.40, were used in this investigation. The nozzle for configuration 1 was an 18-deg, half-angle conical nozzle with an area ratio of 18.00, and the nozzle for configuration 2 was a 7.58-deg, half-angle conical nozzle with an area ratio of 10.76. The stagnation conditions for the driving fluids ranged in pressure from 51 to 866 psia and temperature from 450 to 516 R. The cell-to-driving fluid pressure ratios PcPt for the different driving fluids were dependent on the ratio of specific heats, gamma. An increase in gamma resulting from a decrease in temperture, such as for hydrogen, produced a decrease in PcPt. A decrease in gamma resulting from the change from a single-phase to a two-phase fluid condensation, such as for air, nitrogen, and argon, caused the PcPt ratios to increase.
- Hydraulic and Pneumatic Equipment